With the introduction and widespread adoption in many industries of automatically operated liquid dispensing machines, such as the cam driven machines disclosed in U.S. Pat. No. 4,155,272--issued May 2, 1979 for a "Low Cost Cam Controlled Positioning Apparatus", and in U.S. Pat. No. 4,306,464--issued Dec. 22, 1981 for a "Multi-Directional Mechanical Positioning Apparatus"--Ralph S. Mosher, inventor, and assigned to Robotics, Inc. of Ballston Spa, New York, USA, and with numerical control machines programmed for automatic liquid dispensing, a problem arises during operation of such automatic dispensing machines upon the occurrence of a bubble or void in the liquid mastic, adhesive, sealant, etc., being automatically dispensed. For example, if the automatic dispensing machine is dispensing a medium viscosity liquid such as a silicone sealant around a valve cover for the head of an automotive engine for use as a gasket, the occurrence of a bubble or void in the sealant at a particular point in the travel of the automatically positioned sealant dispensing gun, could result in a leak in the gasket being formed. In order to avoid the production of such faults in automatically dispensed medium to high viscosity liquids, the present invention was devised.